Fix a Slow Mac

Having a slow iMac, MacBook or MacMini can really take the joy out of the Apple computing experience.

Our Apple Mac overhaul, clean-up and upgrade service can put the joy back into using Mac again!

Common Symptoms of a Slow iMac, MacBook or MacMini include:

  • Your Mac OS (Mojave etc.,) is slow to start-up

  • Spinning wheel or beachball when accessing emails using Mail App or Outlook.

  • Your Mac freezes or beachballs when using Microsoft Word or Outlook

  • Your Mac freezes when browsing the internet using Safari, Firefox or Chrome

  • Your Mac is slow after installing an update

  • Your Mac is slow after upgrading to a newer operating system such as High Sierra (10.13) or Mojave (10.14)

  • Mail App is very slow

  • Time Machine back-ups takes ages to complete

  • Your Mac takes a long time to shut down

Why is my iMac / MacBook so slow?

There are numerous possible reasons why your iMac or MacBook is slow. It might be due to insufficient RAM, corrupt operating system files or you might have an incompatible or failing hard disk.

Lack of RAM (Memory) Onboard

In certain instances, the root cause of your iMacs or MacBook’s slowness might be a lack of RAM (otherwise referred to as memory). For example, only having 4GB of RAM onboard your iMac or MacBook, its going to be slow. We can upgrade your Mac’s memory using quality DDR3 and DDR4 ECC RAM. For those using memory intensive applications, we can upgrade your 8GB to 16GB or from 16GB to 32GB.

Check your Mac for CPU Runaway Proceses

Every application on your Mac should use CPU resources according to its design parameters. The central processing unit (CPU) is like the engine for your Mac. However, there are times when an application will start devouring your CPU resources resulting in systemwide slow and laggy performance. According to Apples’s official documentation, in the Activity Monitor a process can be classified as “runaway” if it consistency uses more than 70% of the CPU. (The “kernel task” process is the exception here) For example, CleanMyMac and McAfee are notorious applications for gobbling up CPU cycles. You can use Activity Monitor to find what specific applications are using the most CPU resources on your Mac. Go to Applications > Utilities > Activity Monitor.

Clean-up your Desktop

Here is an interesting quirk with MacOS. If your desktop is chock full of large files. This can significantly slow down the boot-up process of your iMac, MacBook or MacMini. So, while storing folders on your desktop might be very convenient – don’t do it. (Small files like Word, PowerPoint, etc. are fine, but larger folders stored on the desktop containing videos, jpeg's, or PDFs can slow MacOS down)

Repair Permissions

Over time, your Mac operating system may develop small file permission errors. In due course, these can slow down your system. To repair HFS+ or APFS file system errors, power up your system while pressing Command + S simulatenously. This should put your Mac into Single User Mode. You will see a command prompt screen. Type in “fsck -fy”. You may need to run this command twice. After you see “The volume appears to be ok” you can reboot your system by entering the command “reboot”. This will hopefully have cleared any errors.

Reduce the number of Login Items

When your Apple Mac boots up, numerous processes initialise in the background. Some of these may be essential for specific applications that you run. However, others will be superfluous and will just slow your system down. Therefore, it’s generally a good idea to trim your system’s Login Items. Go to Apple Menu > System Perferences > Users and Groups. Select your user account. Click on “Login Items”. To remove an item, press the minus (-) button.

Stop using a Spinning (electro-mechanical) Hard Disk

Probably one of the most effective steps you can take to speed up your Mac is the remove your spinning hard disk (pictured above) and upgrade it to an SSD.

Delete Preference files

If a particular application is slow but the rest of your MacOS runs smootly – the application might have corrupt Preference files. To delete these, open Finder, hold down the Option key, click on Go > Library > Preferences.

Reduce Transparency Effects

If your Mac is straining to run basic applications or file searches, you can eek out some extra performance by disabling “transparency” effects. This user interface feature which makes your operating system look, well…more transparent. Disabling it can make your Mac run slightly faster without affecting MacOS’s functionality. To disable it, go to System Preferences > Accessibility > Display > Click on Reduce Transparency.

Optimise Storage

When you download movies and TV shows from iTunes, they will stay on your local hard disk taking up valuable space. Luckily you can get MacOS to delete them. Go to the Apple menu > About this Mac > Storage > click on manage. Where it says “Optimise Storage” click on “Optimize”. And don’t worry about your movies and TV shows, iTunes will still hold a record of your purchase and you can download them again anytime you feel.

Delete Old Unused Applications

You can delete old applications by simply dragging the Trash icon to the Dock.

Turn off Siri

Under System Settings, turn off Siri if you don’t use it.

Delete corrupt Perference Files

If a particular app is slow, it’s Preference Files might be corrupt. To delete these files. Hold down the option (alt) key and pick Library from the Go menu. Open Preferences and select the preferences you wish to delete e.g. Photoshop.

Frequently Asked Questions about Fixing Slow Macs…

What is the best program to clean my Mac?

Most so-called “cleaning” applications for MacOS do not work! Often, these apps just conflict with the in-built security controls on your Mac’s operating system. While their promoters may claim Mac their speed-up programs do all sorts of wonderful things to boost the speed of your Mac, in reality they are very limited in what they can do. This is due to the closed architecture of MacOS. At worst, these programs just use up CPU and RAM resources on your system and end up slowing your system down.

Is it normal for a brand-new iMac to be slow?

If your brand-new iMac is using a spinning drive (HDD) in conjunction with an APFS-optimised operating system such as Mojave, well yes, it’s normal. The latest versions of Mac operating system do not perform well on spinning hard disks. Typically, disk latency issues will cause your operating system to “beachball”. Therefore, it is strongly advisable you upgrade your disk to an SSD.

Will more memory always make my iMac go faster?

Not necessarily! If you have enough RAM (memory) onboard already, the difference that extra RAM is going to make might not be that significant. A more noticable performance boost can be gained by installing an SSD. These NAND-based disks can significantly boost your iMac’s performance due to their higher IOPS and lower latency rates. This will make rendering tasks such as photo editing run much faster and smoother.

Is my iMac slow because I have too much on it?

Possibly. If you hard disk is more than 80 per cent full, then there is very little “breathing space” left for virtual memory and system cache processes to work efficiently. This can slow down your system. As a general rule of thumb, you should always keep at least 15-20% of your hard disk free.

How do SSDs make macOS High Sierra or Mojave go faster?

With an electro-mechanical hard disk (HDD) an actuator arm has to physically move across the disk platters. This can cause significant latency problems on your system. SSDs don’t have this problem because they use NAND chips which are super-fast in comparison. MacOS Mojave (10.14) and High Sierra (10.13) are optimised to use SSDs as opposed to HDDs.

What’s the difference between an OS “upgrade” and a “clean install”?

With an OS “re-install”, a newer version of the Mac operating system is installed on top of your existing one. Your applications and files are kept more or less intact. This can be performed via the App store. With a “clean install”, your hard disk is wiped and then a new operating system is installed. The major advantage of this method is that corrupt OS system or application files are not migrated over – meaning your system will be running in tip-top condition. (It is imperative that you perform a complete data backup if you choose this option. This can be completed using Time Machine or by using a disk cloning application such as Super Duper).

Ever since upgrading to MacOS Mojave (10.14), my iMac has been running slow?

You’re probably still using a spinning disk (HDD) in your iMac which Mojave is not very compatible with. An SSD upgrade should solve your problem.

A process called “Kernel_task” seems to be using up a high percentage of my Mac’s CPU resources. How do I fix this?

“Kernal_task” if the main process of your Mac’s operating system. When this process starts gobbling up your CPU resources when you system is idle, it can be symptomatic of a hard disk which is failing, reaching full capacity or can be due to some other underlying issue.

A process called “backupd” seems to be appearing a lot in my 27” iMac’s Activity Monitor and is using lots of CPU. How do I fix this?

The “backupd” process is related to Time Machine Backup and is completely normal. However, hyper-activity of this process can be also symptomatic of a failing backup disk.

I recently connected a half-full WD Passport backup drive to my iMac. Since then, processes called “mds” and “mdworker” seem to be running continually and I think are slowing down my Mac?

These processes are part of Spotlight and are completely normal. They are just indexing files on your new disk.

My 4K 2015 Intel Core i5 iMac with a 1TB HDD is almost unsuable and is constantly “beachballing”?

Check your MacOS’s Activity Monitor for any application using an abnormal number of CPU cycles. Assuming there are no underlying problems, installing a good quality SSD from WD, Toshiba or Sandisk will make your system go substanitally faster.

The ventilation grill on 21.5” iMac (left) and dust-laden internal fan (right).

Could dust be slowing down my MacBook?

In theory yes – dust could be a contributing factor. But compared to their Windows-brethern, Apple MacBooks, MacMinis and iMacs tend to induct a lot less dust. If a visual inspection of your systems’s ventilation holes reveals signs of substantial dust accumulations, that might well be your problem.

Will wiping and reinstalling my Mac’s OS make it go faster?

Wiping your Mac and re-installing the operating system might make your system run a small bit faster. However, if there are underlying issues such as an unsuitable hard disk onboard or insufficient RAM, your system is still likely to perform poorly.

Will disk defragmentation make my Mac’s disk hard disk run faster?

Disk defragmentation is usually only effective if your Mac to continually used to write and delete large files (such as audio or video). If this is the case, you might notice a small benefit from defragmenting your disk. Otherwise, using a third-party app to defragment your disk can undo the in-built disk optimisation operations of macOS and is not advisable.

Could a virus or malware be slowing down my Mac?

MacOS is a very secure operating system and while not totally immune from viruses and malware, it’s rare that they will noticeably degrade operating system performance. If your system is infected with malware, you will normally notice visible signs of infection such as continual browser redirects or pop-ups. However, it is important to remember that with a substantial cohort of users the software which slows their system down is the software which they have downloaded themselves!

I have encryption enabled on my MacBook Pro’s hard disk, could FileVault be slowing it down?

In our benchmarking tests, we have found that the performance hit from FileVault is neglible. (Obviously, for disk-instensive tasks such as file copying you will notice a slight slow down relative to an unencrypted disk). Therefore, it’s likely that some other factor is contributing to your Mac’s sluggish performance.